1. Field of the Invention
This invention relates generally to the field of actuators for selectively moving one member relative to another, and, more particularly, to an improved actuator which uses either the products of a hypergolic reaction between a suitable solid or liquid fuel and an oxidizer, or the products of a disassociation reaction between a suitable mono-propellant fuel and a catalyst, to selectively move a valve member relative to its seat.
2. Description of the Prior Art
Actuators abound in many different forms, and are used for many different purposes. Such actuators may be fluid-powered (as in the case of a piston-and-cylinder), or electro-mechanical (as in the case of a solenoid, a force motor, or a torque motor). It is, of course, well known to use such actuators to move a valve element relative to an associated seat.
However, in the field of rocketry and spacecraft, weight is a primary consideration. While actuators may be miniaturized in an attempt to reduce their weight and size, such actuators must also have the capability of creating a force sufficient to displace an applied load. In general, the greater the applied load, the larger and heavier the actuator and any associated valve. Such vehicles typically have a plurality of rocket engines, which are used to either propel the vehicle or to control its attitude during flight (e.g., thrusters).
It is well known to supply a suitable fuel and oxidizer to a hypergolic rocket engine. When such fuel and oxidizer are mixed together, they undergo a hypergolic reaction, and the products thereof create thrust. It is also known to supply a suitable mono-propellant fuel to a rocket engine, which incorporates a suitable triggering catalyst. Upon contact with the catalyst, the fuel undergoes a disassociation reaction, and the products thereof are also used to create thrust. In controlling the operation of these engines, it is necessary to control the flow of the serviced fluid(s) supplied thereto.